Methods involving sensory and motor neuron derived factor (SMDF)

Abstract

A method for activating the HER2 receptor comprising contacting a cell which expresses this receptor with SMDF polypeptides is discussed. A method for enhancing differentiation and/or proliferation of a cell using SMDF polypeptides is also disclosed. These methods may be performed in vitro or in vivo.\!

What is claimed is: 
     
       1. A method for activating HER2 receptor comprising contacting a cell which expresses the HER2 receptor with a polypeptide which activates the HER2 receptor and comprises an amino acid sequence selected from the group consisting of: (a) the amino acid sequence for mature soluble SMDF in SEQ ID NO:2;   (b) allelic variants of (a); and   (c) the amino acid sequences of (a) or (b) having only a single exemplary amino acid substitution as defined in Table 1.   
     
     
       2. The method of claim 1 wherein the cell is present in a mammal. 
     
     
       3. The method of claim 2 wherein the mammal is a human. 
     
     
       4. A method for enhancing differentiation or proliferation of a cell which expresses the HER2 receptor, and the HER3 receptor or the HER4 receptor, comprising contacting the cell with a polypeptide which activates the HER2 receptor and comprises an amino acid sequence selected from the group consisting of: (a) the amino acid sequence for mature soluble SMDF in SEQ ID NO:2;   (b) allelic variants of (a); and   (c) the amino acid sequences of (a) or (b) having only a single exemplary amino acid substitution as defined in Table 1.   
     
     
       5. The method of claim 4 wherein the cell is a glial cell. 
     
     
       6. The method of claim 5 wherein the glial cell is a Schwann cell. 
     
     
       7. The method of claim 4 wherein the cell is present in cell culture. 
     
     
       8. The method of claim 4 wherein the cell is present in a mammal. 
     
     
       9. The method of claim 1 wherein the polypeptide comprises the amino acid sequence for mature soluble SMDF in SEQ ID NO:2. 
     
     
       10. The method of claim 1 wherein the polypeptide comprises a SMDF-immunoglobulin chimera. 
     
     
       11. The method of claim 1 wherein the cell is present in cell culture. 
     
     
       12. The method of claim 4 wherein the polypeptide comprises the amino acid sequence for mature soluble SMDF in SEQ ID NO:2. 
     
     
       13. The method of claim 4 wherein the polypeptide comprises a SMDF-immunoglobulin chimera. 
     
     
       14. The method of claim 4 wherein the cell is a SK-BR-3, hepatocyte, glioblastoma, epithelial, muscle, astrocyte or oligodendrocyte cell. 
     
     
       15. The method of claim 4 which enhances proliferation of the cell. 
     
     
       16. The method of claim 4 which enhances differentiation of the cell. 
     
     
       17. The method of claim 8 wherein the mammal is a human.